The present invention relates to the field of vehicles which travel within pipes, and more particularly, to a vehicle having counter-rotating, dual-vector wheels which can drive the vehicle both vertically and horizontally through a pipe.
Since the early 1970's, internal pipeline vehicles have routinely performed pipe inspections in the oil, gas, and nuclear power industries. Internal conduit vehicles have been designed with conventional circular wheels pressed against the internal surface of the pipe. U.S. Pat. No. 3,890,905, describes a vehicle designed to travel inside a pipe. The vehicle includes a pair of counter-rotating drive members around which circular wheels are attached. The spin axes of the wheels are angled with respect to the axis of the pipe so that rotation of the drive members produces a driving force which causes the vehicle to move through the pipe. The drive wheels are spring loaded to maintain constant contact between the wheels and the interior walls of the pipe. The angles of the spin axes of each wheel provide the vehicle with both rotational and axial thrust as the drive members rotate. One limitation of circular wheels is that they tend to provide insufficient traction for pulling massive loads and for enabling the vehicle to travel vertically through the pipe. Many pipelines have horizontal sections of different elevations, requiring vertical or at least inclined transitions between the sections. Present internal pipe inspection vehicles generally cannot traverse such transitions. Therefore, many sections of pipes cannot be readily inspected.
A need therefore exists for a vehicle capable of pulling increased loads and for traveling vertically through a pipe.